Решите систему уравнении 3m-2n=9 5m-n=15

$\left \{ {{3m - 2n = 9} \atop {5m - n = 15}} \right.$ ⇒ $\left \{ {{3m - 2n = 9 \atop {-10m + 2n = - 30}} \right.$ ⇒ $\left \{ {-7m = -21} \atop {5m - n = 15}} \right.$ ⇒ $\left \{ {{m = -21 : (-7) = 3} \atop {5*3-n=15}} \right.$ ⇒ $\left \{ {{m=3} \atop {n=0}} \right.$

Ответ: ( m; n ) = ( 3; 0 ) или ( n; m ) = ( 0; 3 )